
   function changeImg(){   
    var imgSrc = $("#code_img");   
    var src = imgSrc.attr("src");   
    imgSrc.attr("src",chgUrl(src));   
}   
//时间戳   
//为了使每次生成图片不一致，即不让浏览器读缓存，所以需要加上时间戳   
function chgUrl(url){   
    var timestamp = (new Date()).valueOf();   
    //url = url.substring(0,17);   
    if((url.indexOf("&")>=0)){   
        url = url + "×tamp=" + timestamp;   
    }else{   
        url = url + "?timestamp=" + timestamp;   
    }   
    return url;   
} 


  
